Method of photolithographic patterning

Abstract

A method of photolithographic patterning mainly includes: converting a first photolithographic pattern by a digital transformation in a first magnification to a second photolithographic pattern; producing a first optical reticle corresponding to the second photolithographic pattern by an initial lithography in a 1-to-1 image transfer; fabricating a second optical reticle on a transparent substrate by a first photolithography in a first demagnification corresponding to the first optical reticle; and fabricating a microscopic pattern of same dimension as the first photolithographic pattern on a wafer substrate by a second demagnification using the second optical reticle. The multiplication of the first magnification by the first demagnification by the second demagnification equals one. The present invention implements fine patterning on a wafer substrate so as to improve efficiency of photolithographic application.

1 . A method of photolithographic patterning comprising:
 converting a first photolithographic pattern by a digital transformation in a first magnification to a second photolithographic pattern, the first photolithographic pattern and the second photolithographic pattern being in binary image data;   producing a first optical reticle corresponding to the second photolithographic pattern by an initial lithography in a 1-to-1 image transfer, the first optical reticle having a first fiducial alignment mark;   fabricating a second optical reticle on a transparent substrate by a first photolithography in a first demagnification corresponding to the first optical reticle, the second optical reticles having a second fiducial alignment mark corresponding to the first fiducial alignment mark;   fabricating a microscopic pattern of same dimension as the first photolithographic pattern on a wafer substrate by a second demagnification using the second optical reticle, and the microscopic pattern having a third fiducial alignment mark corresponding to the second fiducial alignment mark; and   wherein multiplication of the first magnification by the first demagnification by the second demagnification equals one.   
     
     
         2 . The method according to  claim 1 , wherein the digital transformation comprises a process of optical proximity correction. 
     
     
         3 . The method according to  claim 1 , wherein the transparent substrate is a quartz class wafer. 
     
     
         4 . The method according to  claim 1 , wherein the second optical reticle is a micro to nano scale opaque thin film pattern made of one or any combination of chrome, chrome oxide and chrome oxynitride, titanium, titanium nitride, rubidium, molybdenum and molybdenum silicide, tantalum and tantalum nitride, tungsten, and ruthenium. 
     
     
         5 . The method according to  claim 1 , wherein the first optical reticle comprises a phase shifter in a thin film microstructure. 
     
     
         6 . The method according to  claim 5 , wherein the phase shifter is made of opaque material of one or any combination of chrome, chrome oxide and chrome oxynitride, titanium, titanium nitride, tantalum and tantalum nitride. 
     
     
         7 . The method according to  claim 1 , wherein the first photolithographic pattern comprises a first clear-field photolithographic pattern and a first dark-field photolithographic pattern, the second photolithographic pattern comprises a second clear-field photolithographic pattern and a second dark-field photolithographic pattern, the step of converting the first photolithographic pattern to the second photolithographic pattern comprises: converting the first clear-field photolithographic pattern to the second clear-field photolithographic pattern, and converting the first dark-field photolithographic pattern to the second dark-field photolithographic pattern;
 the step of producing the first optical reticle corresponding to the second photolithographic pattern comprises: producing a first clear-field optical reticle corresponding to the second clear-field photolithographic pattern and a first dark-field optical reticle corresponding to the second dark-field photolithographic pattern, the first clear-field optical reticle having a first clear-field fiducial alignment mark, and the first dark-field optical reticle having a first dark-field fiducial alignment mark;   the step of fabricating the second optical reticle corresponding to the first optical reticle comprises: fabricating the second clear-field optical reticle corresponding to the first clear-field optical reticle and the second dark-field optical reticle corresponding to the first dark-field optical reticle; the second clear-field optical reticle and the second dark-field optical reticle being not overlapped and disposed one next to another side by side; the second clear-field optical reticle having a second clear-field fiducial alignment mark, and the second dark-field optical reticle having a second dark-field fiducial alignment mark.   
     
     
         8 . The method according to  claim 7 , wherein the step of fabricating the microscopic pattern of same dimension as the first photolithographic pattern on the wafer substrate by the second demagnification using the second optical reticle comprises:
 fabricating a clear-field microscopic pattern of same dimension as the first clear-field photolithographic pattern on a first wafer substrate by a second photolithography in the second demagnification using the second clear-field optical reticle; and the clear-field microscopic pattern having a third clear-field fiducial alignment mark corresponding to the second clear-field fiducial alignment mark; and   fabricating a dark-field microscopic pattern of same dimension as the first dark-field photolithographic pattern on a second wafer substrate by a second photolithography in the second demagnification using the second dark-field optical reticle; and the dark-field microscopic pattern having a third dark-field fiducial alignment mark corresponding to the second dark-field fiducial alignment mark.   
     
     
         9 . The method according to  claim 8 , wherein the digital transformation and/or the second photolithography comprises a process of optical proximity correction. 
     
     
         10 . The method according to  claim 7 , wherein the step of fabricating the microscopic pattern of same dimension as the first photolithographic pattern on the wafer substrate by the second demagnification using the second optical reticle comprises:
 fabricating a clear-field microscopic pattern of same dimension as the first clear-field photolithographic pattern on the wafer substrate by a second photolithography in the second demagnification using the second clear-field optical reticle; and the clear-field microscopic pattern having a third clear-field fiducial alignment mark corresponding to the second clear-field fiducial alignment mark; and   fabricating a dark-field microscopic pattern of same dimension as the first dark-field photolithographic pattern on the wafer substrate by a third photolithography in the second demagnification using the second dark-field optical reticle; and the dark-field microscopic pattern having a fourth dark-field fiducial alignment mark to the second dark-field fiducial alignment mark; the dark-field microscopic pattern being disposed above or under the clear-field microscopic pattern horizontally overlapped; the third clear-field fiducial alignment mark and the fourth dark-field fiducial alignment mark being vertically aligned.   
     
     
         11 . The method according to  claim 10 , wherein the digital transformation, the second photolithography and/or the third photolithography comprises a process of optical proximity correction.